Science Experiment Worksheet:
A hypothesis about the relationship between two variables predicts how one variable affects the other. It should be testable and falsifiable by experiment.
When discussing an experiment you need also to consider possible sources of error and validity of the experiments and be able to suggest ways in which the experiment's reliability could be improved. You should be able to reach a conclusion about the data and use of statistical tests, and perhaps make suggestions for further experimental work.
The practical skills that you will develop during your course are tested by a practical examination. In this examination, you will work in a laboratory, answering questions on an examination paper. The questions will test a range of skills, which can be classified into three groups:
- manipulation, measurement and observation
- presentation of data and observation
- analysis, conclusions and evaluations
Vinegar and lemon juice both have a sour taste. Substances with a sour taste contain an acid. Some substances containing acids cannot be tasted.
Experiment-1:
When baking soda is mixed with vinegar, something new is formed. The mixture quickly foams up with carbon dioxide gas. If enough vinegar is used, all of the baking soda can be made to react and disappear into the vinegar solution.
When vinegar and baking soda are first mixed together, hydrogen ions in the vinegar react with the sodium and bicarbonate ions in the baking soda. The result of this initial reaction is two new chemicals: carbonic acid and sodium acetate.
The second reaction is a decomposition reaction. The carbonic acid formed as a result of the first reaction immediately begins to decompose into water and carbon dioxide gas.
Experiment-2:
Q. Air is necessary for a candle to keep burning prove with an experiment.
Ans: We can explain that oxygen is necessary for a candle to keep burning through this experiment.
Aim:
To prove that air is necessary for a candle to keep burning.
Things required:
i) candle ii) jar iii) matchbox
Procedure:
i) Put the candle at the bottom of the jar.
ii) Light the candle and let it burn for a while.
iii) Cover the jar and observe.
Observation:
The candle in a closed container cannot keep burning because oxygen in the container is used up.
Result:
From this experiment, we know that Air is necessary for a candle to keep burning.
Experiment-3:
How can we prove that air has weight? Show with an experiment.
We can prove that air has weight by the following experiment
Aim:
To prove that air has weight.
Things required:
I) a beam balance ii) two balloons iii) strings
iv) a sharp needle
Procedure:
I) we blow two balloons until they are equal in size and tie
ii) we attach the balloons to the balance as shown in the figure.
iii) We make sure that the balance is perfectly horizontal.
iv) We prick one balloon with a needle near the tie and observe what happens to the balloon and the balance.
Observation:
When we prick one of the balloons with a needle the balance will till towards the inflated balloon. Because the balloon still has air inside it and is heavier than the deflated balloon.
Result:
From this experiment, we come to know that air has weight.
Experiment -4:
Aim: to learn that heating causes things to expand and cooling causes things to contract.
Materials needed:
An empty water bottle, a balloon, hot water, cold water or ice cubes, and two bowls or trays.
Method:
1. Fill one bowl or tray with hot water and the other with cold water or ice cubes.
2. Stretch the balloon over the mouth of the bottle.
3. Put the bottle in the hot water and observe.
4. Now put the bottle in the cold water and observe.
Observation:
When the bottle is kept in hot water, the balloon inflates. When the bottle is kept in cold water, the balloon deflates.
Conclusion:
The hot water heats up the bottle and then the air inside it. The heated air rises up and inflates the balloon, causing it to expand in size. The cold water cools down the bottle and then the air inside it. The cold air comes down and deflates the balloon, causing it to contract. Thus, heating causes things to expand and cooling causes things to contract.
Experiment - 5 :
Aim:
To grow a plant from a carrot top
Materials needed:
A carrot, a shallow container, and water.
Method:
1. Cut off the top portion (the end that has left) of a carrot and place it in a container with the bottom part downward. Remove all the leaves from the carrot top.
2. Add water to the container till half the carrot is covered with water.
3. Keep the container in a sunny place.
Observation:
After some days, new leaves sprout from the carrot top.
Experiment - 6:
Aim: Using a lever
things needed:
A wooden ruler ( 30 cm long), a cardboard tube, two erasers, four coins, and adhesive tape.
Method:
1. Place the wooden ruler over the cardboard tube to make a lever.
2. Place the erasers over near one end.
3. Place the coins at the shorter end of the lever.
Observation:
The erasers placed over the longer end would be able to lift the coins on the shorter end. If this does not happen, adjust the fulcrum so that it is closer to the side on which the coins are placed.
Energy Experiment -7:
Q. 1. Energy can produce light and heat prove
with an experiment.
Ans:
Aim: To prove that energy can produce light and heat.
Things required: Table, candle and matchbox.
Procedure:
1. We prepare a candle on a desk.
2. Make the room dark, and then light the candle.
3. We observe what happens to the room and the candle.
4. Then we bring our hand close to the lighted candle and we observe what happens to our hand.
Observation:
When we light a candle in the dark, the room becomes brighter slowly and we are able to see. When we bring our hand close to the lighted candle our hand feels hot and we move our hand away, from the lighted candle.
Result:
From this experiment, we come to know that energy can produce light and heat.
Experiment -8:
Aim:
To observe the air pressure in a dropper.
Things needed:
A dropper and colourful water or ink.
Method:
1. Press the bulb of the dropper.
2. Lower the dropper in colourful water, keeping the bulb pressed.
3. Now release the bulb.
Observation:
Water is sucked up into the tube of the dropper.
Conclusion:
When the bulb is pressed air goes out of the dropper. When it is released in water, the air pushes the colourful water into the dropper.
Experiment -9:
Aim: To prove that air occupies space.
Things needed: A tub filled with water and a glass
Method:
1. Hold a glass upside down over the water in the tub and push it down without tilting the glass.
2. Observe whether water enters the glass.
3. Now, tilt the glass slightly and observe what happens.
Observation:
During the first step, water does not enter the glass, no matter how much it is pushed into the water. But when the glass is tilted, bubbles of air escape from the glass and water fills the space inside the glass.
Conclusion:
This shows that air occupies space.
Experiment -10:
Aim: To prove that air exerts pressure.
Things needed:
A juice can, a glass and a screwdriver
Method:
1. Ask an adult to make a hole in the can with the screwdriver.
2. try pouring the juice into a glass.
3. Now, ask him/her to make another hole, a little away from the first one.
4. Try pouring the juice into the glass.
Observation:
When you first try to pour the juice out, it either does not come out or comes out very slowly. After the second hole is made, it flows out rapidly.
Conclusion:
Air enters the can from the second hole and its pressure pushes the juice out of the can.