Variables & Values

• Have you done any experiments to investigated variables?

• What were the variables?• What were the values you used?

Input & Outcome

• In an experiment what is an:-• input variable• outcome variable

• What happens when there are:-• two input variables • and • one outcome

Yeast

What is Yeast?

• Is Yeast Alive?• How do we know?

• What do living things do?• What do living things need?

What does Yeast need to Grow?

• What is the food for Yeast?• What else would yeast need?

• Warmth?

• How do we know if the yeast is growing/alive?

Activity 1

• Planning an experiment to investigate the activity of yeast.

• Discuss & Decide

• How can you do a fair test for the effect of sugar, the effect of warmth, and the effect of both together on the activity of yeast?

Activity 1

• What are the input variables?• What are the values?• What is the outcome variable?• What is/are the values

Think about the different combinations.

• How many test tubes will you need?

• What outcome would you look for?

Lesson 16

Room Temp. Warm Water

No Sugar

Sugar

Copy the results chart onto the first inside page of your book.Each person willset up one of the tes-tubes.In your group decide which test-tube you are going to do and write your name in the box.

• Place balloon over the test-tube.

• Leave the experiment for 25 minutes.• Go on to activity 3.

Activity 3 Zinc and Copper with Acid

• Put one piece of copper metal into a test tube, another piece of zinc metal into another test tube. Into a third test tube add both a piece of zinc and a piece of copper.

• Add about 1cm3 of de-ionized water to each tube. Observe what happens.

Activity 3 Zinc and Copper with acid

• Add another 1cm 3 of dilute hydrochloric acid to each tube.

• Observe what happens.

Activity 3 Zinc and Copper with acid

• What are the input variables ?

• What is the outcome variable?

Activity 3 Zinc and Copper with acid

Copper Zinc Copper & Zinc

Water

Acid

Activity 3 Zinc and Copper with acid

• Write a group sentence about the reaction of copper and zinc reacting with dilute hydrochloric acid, using the word interact.

Activity 2 Yeast Results

• Measure the amount of froth in each of the yeast experiments or look how much the baloon has blown up.

• Record your results and answer questions 1, 2 & 3.

Not warm (room temp.)

Warm (35o)

No Sugar

Sugar

Activity 2 Yeast Results

What has happened in this experiment?Did you expect these results?

Not warm (room temp.)

Warm (35o)

No Sugar

Sugar

Activity 2 Yeast Results

Q 4. Write a sentence about yeast, sugar, warmth, using the word interact.

• What other examples where two things work together to cause something to happen.

Thinking back

• What was difficult about this lesson?

• How did you solve the problems you had?

Homework for next lesson.

• Finish page 1 & 2.

• Can you think of some other situations were two things interact.

Balloon Experiment“Inflating” balloon

• Put 5 cm3 water into the test-tube. • Put one spatula measure of instant yeast

into the test-tube.

• Put one spatula measure of sugar into two of the test-tubes.

Place balloon over the test-tube.

Lesson 161. Add 5cm3 of yeast mixture to four test tubes.

2. Add 2cm3 sugar solution to two of the test tubes.

2. Stick labels on the test-tubes.(Name, Temperature & Sugar)

4. Put two of the test-tubes into the water bath and leave two in the test-tube rack.

• Repeat the procedure with two more but do not add the sugar.

• Put one in the warm water and leave the other in the test tube rack.

• Leave the experiment for 25 minutes.