HELP

1  Leroy is doing an experiment to find the energy provided by burning two sorts of biomass.

a Give three things that Leroy must do to make sure that his experiments are fair.

b Give two things that Leroy must do to make sure that his experiments are safe.

c Here is Leroy′s results table.

Type of biomass / Water temperature at start in °C / Water temperature after burning in °C
Sunflower seeds / 16 / 48
Straw / 18 / 37

i Which type of biomass provided the most energy?

ii Explain how you can tell.

d Leroy looked up the amounts of energy from his two types of biomass on the Internet. His experiments gave smaller amounts of energy than the website figures. Suggest why Leroy′s results were too low.


CORE

2 Power stations burn both biomass and fossil fuels to generate electricity.

a What type of energy is stored in both biomass and fossil fuels?

b Biomass is often described as a renewable energy resource. Explain what is meant by ′renewable energy resource′.

c Give one advantage of using biomass instead of fossil fuels.

d What are the products when both types of fuel are burnt?

e Explain why using these fuels is bad for the environment.

3 a Photosynthesis produces glucose. Name two ways that plants use the glucose.

b Some plants store the glucose in their roots. In what form is it stored?

c Explain why they store some of the glucose in this way.

EXTENSION

4 a In many plants, much of the glucose from photosynthesis is converted to cellulose. Give one useful product that consists of cellulose.

b Explain why cellulose is important to plants.

5  Sandy did an experiment to find out what substances form the biomass of a geranium leaf. The leaf she chose was green in the centre and white around the edges. The diagram shows her leaf.

Sandy boiled her leaf in alcohol to remove the green colouring.

a What substance should Sandy now put onto the leaf to find out if it contained starch?

b Describe what the leaf would look like after Sandy put this substance onto the leaf.

c Explain why the leaf gave these results.

d How would Sandy′s results have been different if the geranium had been in the dark for several days, before she tested the leaf?

© Harcourt Education Ltd 2004 Catalyst 3

This worksheet may have been altered from the original on the CD-ROM.